Image sensing apparatus and image sensing method

ABSTRACT

An object of this invention is to allow quickly, reliably confirming an in-focus state with a simple arrangement. To achieve this object, an image sensing apparatus includes an image sensing element which photoelectrically converts an object image, a first image generation unit which generates a first image obtained from the image sensing element, a second image generation unit which generates a second image of a predetermined region from the image obtained by the image sensing element, and an exposure control unit which controls exposure so as to set the second image to appropriate brightness.

FIELD OF THE INVENTION

[0001] The present invention relates to an image sensing apparatus suchas an electronic camera, and an image sensing method applied to theapparatus.

BACKGROUND OF THE INVENTION

[0002] The number of pixels of a solid-state image sensing element usedin an electronic camera such as a digital camera is at least 1,500,000to 3,000,000 at maximum. The number of pixels tends to increase. Thenumber of pixels of a liquid crystal monitor attached to the electroniccamera is 60,000 to 100,000 at most.

[0003] To use the liquid crystal monitor having a small number of pixelsas a viewfinder, a focus state at a precision necessary for recording orprintout cannot be confirmed. An out-of-focus state is recognized onlywhen an image sensed by the electronic camera is displayed on the screenof a personal computer or printed out by a printer.

[0004] From this, there is proposed an image sensing apparatus whichgenerates two types of images from a sensed image, simultaneouslydisplays the two images on the display screen, and allows confirming ata high precision the focus state of an actually sensed image whiledisplaying the whole screen, as disclosed in, e.g., Japanese PatentLaid-Open No. 11-341331.

[0005] In such conventional camera apparatus, exposure control duringdisplay is performed by so-called average photometry in which the entiresensed image is averaged. In this case, an image for displaying a focusstate does not always have appropriate brightness.

[0006] For example, if an image for displaying a focus state exceeds theappropriate brightness, the user cannot confirm a focus state at a highprecision.

[0007] When two images are simultaneously displayed on the displayscreen, the whole screen display becomes bright depending on an objectto be sensed, and it is difficult to concentrate on an image fordisplaying a focus state.

SUMMARY OF THE INVENTION

[0008] The present invention has been made to overcome the conventionaldrawbacks, and has as its object to allow quickly, reliably confirmingan in-focus state with a simple arrangement.

[0009] To solve the above problems and achieve the above object,according to the first aspect of the present invention, an image sensingmethod is characterized by comprising the steps of: photo-electricallyconverting an object image by an image sensing unit; generating a firstimage obtained from the image sensing unit by a first image generationunit; generating a second image corresponding to a predetermined regionof the object image obtained from the image sensing unit by a secondimage generation unit; controlling an exposure amount so that the secondimage become to have appropriate brightness by an exposure control unit;and correcting signal of the first image so that the first image becometo have appropriate brightness by a brightness correction unit.

[0010] According to the second aspect of the present invention, an imagesensing method is characterized by comprising the steps of:photo-electrically converting an object image by an image sensing unit;generating a first image obtained from the image sensing unit by a firstimage generation unit; generating a second image corresponding to apredetermined region of the object image obtained from the image sensingunit by a second image generation unit; controlling an exposure amountso that the first image become to have appropriate brightness by anexposure control unit; and correcting signal of the second image so thatthe second image become to have appropriate brightness by a brightnesscorrection unit.

[0011] According to the third aspect of the present invention, an imagesensing method is characterized by comprising the steps of:photo-electrically converting an object image by an image sensing unit;generating a first image obtained from the image sensing unit by a firstimage generation unit; generating a second image corresponding to apredetermined region of the object image obtained from the image sensingunit by a second image generation unit; controlling an exposure so thatthe image become to have appropriate brightness by an exposure controlunit; correcting signal of the image so that the image become to haveappropriate brightness by a brightness correction unit; and controllingthe exposure so that the first image become to have appropriatebrightness and controlling to correct the signal of the first image sothat the second image become to have appropriate brightness in the casethat the first mode is selected, and controlling the exposure so thatthe second image become to have appropriate brightness and controllingto correct the signal of the first image so that the first image becometo have appropriate brightness in the case that the second mode isselected, by a control unit.

[0012] Other objects and advantages besides those discussed above shallbe apparent to those skilled in the art from the description of apreferred embodiment of the invention which follows. In the description,reference is made to accompanying drawings, which form a part hereof,and which illustrate an example of the invention. Such example, however,is not exhaustive of the various embodiments of the invention, andtherefore reference is made to the claims which follow the descriptionfor determining the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a block diagram showing the system configuration of animage sensing apparatus according to the first embodiment of the presentinvention;

[0014]FIGS. 2A to 2C are views for explaining display operation in an MFmode in the image sensing apparatus according to the first embodiment ofthe present invention;

[0015]FIG. 3 is a conceptual view showing two-dimensional data transferin the image sensing apparatus according to the first embodiment of thepresent invention;

[0016]FIG. 4 is a flow chart showing the operation flow oftwo-dimensional data transfer in the image sensing apparatus accordingto the first embodiment of the present invention;

[0017]FIGS. 5A and 5B are views showing an example of system operationin the image sensing apparatus according to the first embodiment of thepresent invention;

[0018]FIG. 6 is a block diagram showing the system configuration of animage sensing apparatus according to the third embodiment of the presentinvention;

[0019]FIGS. 7A to 7C are views for explaining display operation in an AFmode in an image sensing apparatus according to the second embodiment ofthe present invention; and

[0020]FIGS. 8A to 8C is a view for explaining display operation in an MFmode in the image sensing apparatus according to the second embodimentof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Preferred embodiments of the present invention will be describedbelow with reference to the accompanying drawings.

[0022] (First Embodiment)

[0023] The first embodiment of the present invention will be describedwith reference to FIGS. 1 to 5B.

[0024]FIG. 1 is a block diagram showing the system configuration of animage sensing apparatus according to the first embodiment. In FIG. 1,reference numeral 100 denotes a CPU (Central Processing Unit) whichcontrols the overall system; 101, an interface circuit (I/F) for the CPU100; 102, a storage medium such as a memory card; 103, an interfacecircuit (I/F) for the storage medium 102; 104, a DRAM (Dynamic RandomAccess Memory) for storing image data, programs, and the like; 105, asystem controller which performs sequential control of the system andcontrol such as bus arbitration; 106, an image sensing lens; 107, afocus driving unit; 123, a stop; and 124, a stop driving unit.

[0025] Reference numeral 108 denotes an image sensing element which iscomprised of a 1-chip CCD (Charge Coupled Device); 109, an A/D converterwhich converts an analog signal into a digital signal; 110, a signalprocessing circuit; 111, a reduction circuit (zooming circuit) whichreduces pixel data in horizontal and vertical directions by sampling,linear interpolation, and the like; 112, a raster/block conversioncircuit which converts raster scan image data zoomed by the reductioncircuit 111 into block scan image data; 113, a raster block conversionbuffer memory which can convert raster data into block scan data; and114, a compression circuit which compresses JPEG data for each block.

[0026] Reference numeral 115 denotes a memory control circuit whichcontrols an extraction circuit 117, the zooming circuit 111, thecompression circuit 114, a reconstruction circuit 120, and the DRAM 104.

[0027] The memory control circuit 115 transfers a raster data outputfrom the reduction circuit 111 to the DRAM 104.

[0028] The memory control circuit 115 transfers an output from thecompression circuit 114 to the DRAM 104.

[0029] The extraction circuit 117 extracts an arbitrary region fromimage data.

[0030] The memory control circuit 115 two-dimensionally transfers anoutput from the extraction circuit 117 to the DRAM 104.

[0031] The memory control circuit 115 synthesizes two image data in theDRAM 104, and two-dimensionally transfers the synthesized data to thereconstruction circuit 120 to be described below.

[0032] The reconstruction circuit 120 executes modulation, addition of async signal, D/A conversion, and the like for image data to generate avideo signal. Reference numeral 121 denotes a liquid crystal monitorwhich serves as a display device and has a smaller number of pixelscapable of displaying an output than the number of pixels of an imagesensing element; and 122, switches such as a switch S_(REC), switchS_(MF), switch S_(F1), switch S_(F2), switch S_(F3), switch S_(F4), andswitch S_(M).

[0033] The switches 122 connected to the CPU 100 will be explained.

[0034] The switch S_(REC) is used to designate recording of a sensedimage. The switch S_(REC) is turned on, and then a sensed image isrecorded on a recording medium. The switch S_(MF) enables manualfocusing. The switch S_(MF) is turned on, then the manual focus mode isset, and the switches S_(F1) and S_(F2) are enabled. The switch S_(M) isused to switch the mode to macro photographing. The switch S_(M) isturned on, then the macro photographing mode is set, and the switchesS_(F3) and S_(F4) are enabled.

[0035]FIGS. 2A to 2C are views for explaining the relationship between asensed image and a display image. FIGS. 2A, 2B, and 2C show examples ofa sensed image. FIG. 2A illustrates a sensed image read from the imagesensing element 108. FIG. 2B shows an entirely reduced image obtained bysampling and reducing, at a predetermined magnification, pixel data ofthe image read from the image sensing element 108, and an imageextracted from the rectangular region of the sensed image in FIG. 2Awithout sampling pixel data of this region. FIG. 2C shows a view angleadjustment image and focus adjustment image which are obtained bysynthesizing the entirely reduced image and extracted image in FIG. 2B,and displayed on the liquid crystal monitor 121 serving as a displaydevice.

[0036] Display operation of the image sensing apparatus according to thefirst embodiment will be explained.

[0037] The image sensing lens 106 can be moved by the focus driving unit107 along the optical axis. The stop 123 inserted in the optical axis isdriven by the stop driving unit 124. The image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing lens 106 is larger in the number of pixels than the monitor 121.

[0038] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby the A/D converter 109. The digital image signal is input to thesignal processing circuit 110. The signal processing circuit 110includes a white balance adjustment circuit, gamma correction circuit,YC processing circuit, and exposure/focus (AE/AF) circuit. The signalprocessing circuit 110 outputs image data processed by these circuits tothe reduction circuit 111 and extraction circuit 117. AE data serving asexposure information is obtained by an AE data creation device from abrightness signal component extracted by an internal brightness signalcomponent extraction circuit. The obtained AE data is supplied to theCPU 100. The extracted brightness signal component is supplied to an AFdata creation device which is comprised of a high-pass filter andintegrator. Only a high-frequency component is extracted using thehigh-pass filter, and integrated using the integrator, obtaining AF dataserving as focus information. The obtained AF data is supplied to theCPU 100.

[0039] The reduction circuit 111 reduces the image data in horizontaland vertical directions by performing sampling, linear interpolation,and the like for pixel data of the sensed image in accordance with thedisplay size of the monitor 121, and outputs the entirely reduced imagedata to the memory control circuit 115. The memory control circuit 115sequentially writes, at a pointer Pa in the DRAM 104 shown in FIG. 5A,the image data of the display size input from the reduction circuit 111,thereby transferring the entirely reduced image data to an entirelyreduced image data memory area.

[0040]FIG. 3 is a conceptual view showing the operation of the memorycontrol circuit 115. When the DRAM 104 is assumed to be atwo-dimensional plane, the memory control circuit 115 transfers data toa rectangular region in the DRAM 104.

[0041] In FIG. 3, P1, P2, P3, P4, P5, and P6 represent addresses; N, thenumber of lines of a rectangular region to which data is transferred;and M, the number of pixels (words) of one line. The values of distancesJ represented by dotted lines are the same and are equal to, e.g., thedistance between P3 and P2. Transfer to the rectangular region can berealized by repeating N times transfer of M words starting from apointer at the left end in FIG. 3.

[0042]FIG. 4 is a flow chart showing the operation flow oftwo-dimensional data transfer. In FIG. 4, P1, M, N, and J correspond toP1, M, N, and J in FIG. 3, and are set in the setting register of thememory control circuit 115.

[0043] In FIG. 4, counter values h and c are reset in step S401. In stepS402, address a is obtained from the counter values h and c(a=P1+h+(M+J)c). In step S403, data is written at address a obtained instep S402. The counter value h is incremented by one (h=h+1) in stepS404, and whether the counter value h is equal to the number M of pixels(words) of one line (h=M) is decided in step S405. If YES in step S405,i.e., one line has been processed, the processing advances to step S406to reset the counter value h (h=0) and increment the counter value c byone (c=c+1). In step S407, the number of lines is compared to decidewhether the number of lines is equal to the number N of lines of therectangular region to which data is transferred (c=N). If YES in stepS407, i.e., data for all lines have been transferred, the processingoperation ends.

[0044] If NO in step S405 or S407, the processing returns to step S402to perform transfer for the next line.

[0045] This processing realizes two-dimensional data transfer.

[0046] The CPU 100 reads out, from the signal processing circuit 110,brightness information in a region from which a predetermined partialimage is to be extracted. The CPU 100 controls the accumulation time(electronic shutter) of the image sensing element 108 and the f-numberof the stop 123 so as to give appropriate brightness to thepredetermined partial image. Accordingly, the predetermined partialimage attains appropriate brightness.

[0047] The extraction circuit 117 extracts the predetermined partialimage without sampling pixel data from image signals of one frame(without decreasing the number of pixels), and outputs an image signalrepresenting the extracted partial image to the memory control circuit115. The memory control circuit 115 sequentially writes image data ofthe partial image input from the extraction circuit 117 at a pointer Pbin the DRAM 104 shown in FIG. 5A, thereby transferring the extractedpartial image data to an extracted partial image memory area.

[0048] The memory control circuit 115 reads out the entirely reducedimage data and extracted partial image data in the DRAM 104 inaccordance with the display position. The memory control circuit 115synthesizes the entirely reduced image data and extracted partial image,and outputs the resultant data as synthesized image data to thereconstruction circuit 120.

[0049]FIGS. 5A and 5B are conceptual views showing data transferoperation of the memory control circuit 115 to the reconstructioncircuit 120. In FIG. 5A, Pa, Pb, and Pc represent pointers in the DRAM104. In FIG. 5B, P1 and P2 represent pointers. When data falls outsidethe range of numerical values represented by the pointers P1 and P2, theaddress of an entirely reduced image in FIG. 5A is generated. When datafalls within the range of the numerical values represented by thepointers P1 and P2, the image is switched to an extracted image in FIG.5A to generate an address, and synthesized image data is output.

[0050] The reconstruction circuit 120 executes signal processing such aschroma encoding, band correction, or compositeness for the synthesizedimage data input from the memory control circuit 115, thereby convertingthe data into a TV (TeleVision) analog signal. The reconstructioncircuit 120 outputs the video signal to the monitor 121.

[0051] As described above, according to the image sensing method andapparatus of the first embodiment, the in-focus state of an image sensedby the image sensing element 108 having a large number of pixels can beproperly confirmed with appropriate brightness on the monitor 121 havinga small number of pixels. The user can manually adjust the focus at ahigh precision while confirming an entire frame and focus adjustmentframe free from any timing difference.

[0052] (Second Embodiment)

[0053] The second embodiment will be described with reference to FIGS. 1and 7A to 7C.

[0054] The basic system configuration of an image sensing apparatusaccording to the second embodiment is the same as that in FIG. 1according to the first embodiment described above. Display in the MFmode is illustrated in FIGS. 2A to 2C, similar to the first embodiment.An example of system operation is shown in FIGS. 5A and 5B, similar tothe first embodiment. The second embodiment will be explained withreference to these drawings.

[0055] The second embodiment is applied to an electronic camera havingan autofocus (to be referred to as AF hereinafter) function ofautomatically adjusting the focus on an image, and a manual focus (to bereferred to as MF hereinafter) function of adjusting the focus manually(including electrically).

[0056]FIGS. 7A to 7C are views for explaining the relationship between asensed image and a display image. FIGS. 7A, 7B, and 7C show examples ofa sensed image. FIG. 7A illustrates an image read from an image sensingelement 108. FIG. 7B shows a reduced image obtained by zooming, at apredetermined magnification, the image read from the image sensingelement 108. FIG. 7C shows the reduced image in FIG. 7B displayed on amonitor 121 serving as a display device.

[0057] Display operation of the image sensing apparatus according to thesecond embodiment will be explained.

[0058] The second embodiment is different from the first embodiment inthat a signal processing circuit 110 comprises an exposure/focus (AE/AF)circuit. The signal processing circuit 110 includes a white balanceadjustment circuit, gamma correction circuit, and YC circuit. Image dataprocessed by these circuits are output to a reduction circuit 111 andextraction circuit 117. AE data serving as exposure information isobtained by an AE data creation device from a brightness signalcomponent extracted by an internal brightness signal componentextraction circuit. The obtained AE data is supplied to a CPU 100. Theextracted brightness signal component is supplied to an AF data creationdevice which is comprised of a high-pass filter and integrator. Only ahigh-frequency component is extracted using the high-pass filter, andintegrated using the integrator, obtaining AF data serving as focusinformation. The obtained AF data is supplied to the CPU 100.

[0059] Display operation of the image sensing apparatus according to thesecond embodiment will be described in detail.

[0060] More specifically, image data of 1,600 horizontal pixels and1,200 vertical pixels at the aspect ratio of the image size=4:3 isreduced to 640×480 by the reduction circuit 111. In the MF mode, a320×240 partial image is extracted by the extraction circuit 117. The640×480 image data reduced by the reduction circuit 111 and the 320×240partial image extracted by the extraction circuit 117 are displayed onthe monitor 121. This example will be explained.

[0061] An image sensing lens 106 can be moved by a focus driving unit107 along the optical axis. A stop 123 inserted in the optical axis isdriven by a stop driving unit 124. The image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing element 108 outputs image data of 1,600 horizontal pixels and1,200 vertical pixels. The monitor 121 displays image data of 640horizontal pixels and 480 vertical pixels.

[0062] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby an A/D converter 109. The digital image signal is input to the signalprocessing circuit 110. The signal processing circuit 110 includes thewhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies AE data and AF data at the entireview angle to the CPU 100.

[0063] The CPU 100 calculates stop control information and anaccumulation time on the basis of the AE data, and supplies theaccumulation time (electronic shutter) information to the driving unitof the image sensing element 108 and the stop control information to thedriving circuit 124 of the stop 123. When the AF mode is set (thesetting of the AF mode corresponds to an initial state in which the MFmode is not set by a switch S_(MF) out of switches 122), the CPU 100 cangenerate focus control information on the basis of the AF data obtainedalong with the operation of a focus mechanism, drive the focus drivingunit 107, and automatically set the image sensing lens 106 to anin-focus position.

[0064] The reduction circuit 111 reduces pixel data in horizontal andvertical directions by performing sampling, linear interpolation, andthe like for pixel data in accordance with the display size of themonitor 121 (see FIG. 7B), and outputs the entirely reduced image datato a memory control circuit 115. The memory control circuit 115sequentially writes, at a pointer Pa in a DRAM 104 shown in FIG. 5A, theimage data of the display size input from the reduction circuit (zoomingcircuit) 111, thereby transferring the entirely reduced image data to anentirely reduced image data memory area.

[0065] The memory control circuit 115 reads out the entirely reducedimage data in the DRAM 104 in accordance with the display position, andoutputs the entirely reduced image data to a reconstruction circuit 120.

[0066] The reconstruction circuit 120 executes signal processing such aschroma encoding, band correction, or compositeness for the entirelyreduced image data input from the memory control circuit 115, therebyconverting the data into a TV (TeleVision) analog signal. Thereconstruction circuit 120 outputs the video signal to the monitor 121(see FIG. 7C).

[0067] When the AF mode is switched to the MF mode (the setting of theMF mode corresponds to a state in which the MF mode is set by the switchS_(MF) out of the switches 122), the CPU 100 stops auto focus controlbased on the AF data, switches the mode to the manual focus mode, andenables switches S_(F1) and S_(F2).

[0068] The switch S_(F1) is used to designate to drive the focus drivingunit 107 and drive the image sensing lens 106 to infinity. The switchS_(F2) is used to designate to drive the focus driving unit 107 anddrive the image sensing lens 106 to the closest focusing side.

[0069] An object image (see FIG. 2A) formed on the image sensing surfaceof the image sensing element 108 is photoelectrically converted by theimage sensing element 108, and sequentially read as CCD signals. EachCCD signal is converted from an analog signal into a digital signal bythe A/D converter 109. The digital image signal is input to the signalprocessing circuit 110. The signal processing circuit 110 includes thewhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies, to the CPU 100, AE data and AFdata of partial image data extracted by the extraction circuit 117.

[0070] The CPU 100 calculates stop control information and anaccumulation time on the basis of the AE data, and supplies theaccumulation time (electronic shutter) information to the driving unitof the image sensing element 108 and the stop control information to thedriving circuit 124 of the stop 123.

[0071] Hence, the partial image data extracted by the extraction circuit117 attains appropriate brightness.

[0072] The extraction circuit 117 generates an address, and outputsimage data at a portion within the range of numerical values representedby pointers P1 and P2 shown in FIG. 2A from image signals of 1,600horizontal pixels and 1,200 vertical pixels of one frame that are inputfrom the signal processing circuit 110. When data falls outside therange of the numerical values represented by the pointer P1 (640horizontal pixels and 480 vertical pixels) and the pointer P2 (960horizontal pixels and 720 vertical pixels) shown in FIG. 2A, theextraction circuit 117 does not output any image data. The extractioncircuit 117 extracts a partial image of 320 horizontal pixels and 240vertical pixels without sampling (without decreasing the number ofpixels), and outputs an image signal representing the extracted partialimage to the memory control circuit 115. The memory control circuit 115sequentially writes image data of the 320×240 partial image input fromthe extraction circuit 117 at a pointer Pb in the DRAM 104 shown in FIG.5A, thereby transferring the extracted partial image data to anextracted partial image memory area.

[0073] The memory control circuit 115 reads out the 640×480 entirelyreduced image data and the 320×240 extracted partial image data in theDRAM 104 in accordance with the display position. The memory controlcircuit 115 synthesizes the entirely reduced image data and extractedpartial image, and outputs the resultant data as synthesized image datato the reconstruction circuit 120.

[0074] When the focus mode is switched from the AF mode to the MF modeby operating the switch S_(MF) in photographing, the monitor 121 changesfrom a state in which a sensed image is displayed as shown in FIG. 7C,and displays the entirely reduced image data and the predeterminedappropriate-brightness partial image extracted using a predeterminedposition of the image as a center, as shown in FIG. 2C. While monitoringthe focus adjustment image in FIG. 2C, the user can operate the switchesS_(F1) and S_(F2), move the image sensing lens 106 forward or backward,and focus it on an object to be sensed.

[0075] The focus adjustment image is an appropriate-brightness imagewhich is extracted using a predetermined position of an image sensingsignal as a center without decreasing the number of pixels. The usercan, therefore, confirm the same state as the focus state of a recordedimage.

[0076] The view angle adjustment image in FIG. 2C is simultaneouslydisplayed on the monitor 121. Even if the user changes an object to besensed, he/she can focus the image sensing lens 106 on the object whileconfirming the entire view angle.

[0077] When the MF mode is switched to the AF mode (the switch S_(MF)out of the switches 122 is released), the CPU 100 inhibits theextraction circuit 117 and control of the memory control circuit 115from the extraction circuit 117. The memory control circuit 115 readsout entirely reduced image data in the DRAM 104, and outputs it to thereconstruction circuit 120, setting the states in FIGS. 7A to 7C. Afterthat, the CPU 100 is set in the AF mode.

[0078] In the second embodiment, entirely reduced image data correspondsto 640×480 pixels, and an extracted image corresponds to 320×240 pixels.Alternatively, as shown in FIGS. 8A to 8C, entirely reduced image datamay correspond to 320×240 pixels, and an extracted image may correspondto 640×480 pixels.

[0079] Also, images in FIGS. 8A to 8C and 2A to 2C may be switched.

[0080] The remaining arrangement, operation, and effects of the secondembodiment are the same as those of the first embodiment, and adescription thereof will be omitted.

[0081] (Third Embodiment)

[0082] The third embodiment of the present invention will be describedwith reference to FIG. 6.

[0083] The basic system configuration of an image sensing apparatusaccording to the third embodiment is the same as that in FIG. 1according to the first embodiment described above. Display in the MFmode is illustrated in FIGS. 2A to 2C, similar to the first embodiment.In FIG. 6, the same reference numerals as in FIG. 1 according to thefirst embodiment denote the same parts. An example of system operationis shown in FIGS. 5A and 5B, similar to the first embodiment. The thirdembodiment will be explained with reference to these drawings.

[0084] The third embodiment is applied to an electronic camera having anautofocus (to be referred to as AF hereinafter) function ofautomatically adjusting the focus on an image, and a manual focus (to bereferred to as MF hereinafter) function of adjusting the focus manually(including electrically).

[0085]FIG. 6 is different from FIG. 1 in that a second signal processingcircuit 130 which performs predetermined gain signal processing for thebrightness signal component of an image signal reduced by a reductioncircuit 111 is interposed between the reduction circuit 111 and a memorycontrol circuit 115, and a third signal processing circuit 131 whichperforms predetermined gain signal processing for the brightness signalcomponent of an image signal extracted by an extraction circuit 117 isinterposed between the extraction circuit 117 and the memory controlcircuit 115. In FIG. 6, the same reference numerals as in FIG. 1according to the first embodiment denote the same parts.

[0086]FIGS. 7A to 7C are views for explaining the relationship between asensed image and a display image. FIGS. 7A, 7B, and 7C show examples ofa sensed image. FIG. 7A illustrates an image read from an image sensingelement 108. FIG. 7B shows a reduced image obtained by zooming, at apredetermined magnification, the image read from the image sensingelement 108. FIG. 7C shows the reduced image in FIG. 7B displayed on amonitor 121 serving as a display device.

[0087] Display operation of the image sensing apparatus according to thethird embodiment will be explained.

[0088] More specifically, image data of 1,600 horizontal pixels and1,200 vertical pixels at the aspect ratio of the image size=4:3 isreduced to 640×480 by the reduction circuit 111. In the MF mode, a320×240 partial image is extracted by the extraction circuit 117. The640×480 image data reduced by the reduction circuit 111 and the 320×240partial image extracted by the extraction circuit 117 are displayed onthe monitor 121. This example will be explained.

[0089] An image sensing lens 106 can be moved by a focus driving unit107 along the optical axis. A stop 123 inserted in the optical axis isdriven by a stop driving unit 124. The image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing element 108 outputs image data of 1,600 horizontal pixels and1,200 vertical pixels. The monitor 121 displays image data of 640horizontal pixels and 480 vertical pixels.

[0090] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby an A/D converter 109. The digital image signal is input to a signalprocessing circuit 110. The signal processing circuit 110 includes awhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies AE data and AF data at the entireview angle to a CPU 100.

[0091] The CPU 100 calculates stop control information and anaccumulation time on the basis of the AE data at the entire view angle,and supplies the accumulation time (electronic shutter) information tothe driving unit of the image sensing element 108 and the stop controlinformation to the driving circuit 124 of the stop 123. When the AF modeis set (the setting of the AF mode corresponds to an initial state inwhich the MF mode is not set by a switch S_(MF) out of switches 122),the CPU 100 can generate focus control information on the basis of theAF data obtained along with the operation of a focus mechanism, drivethe focus driving unit 107, and automatically set the image sensing lens106 to an in-focus position.

[0092] The reduction circuit 111 reduces pixel data in horizontal andvertical directions by performing sampling, linear interpolation, andthe like for pixel data in accordance with the display size of themonitor 121 (see FIG. 7B), and outputs the entirely reduced image datato the second signal processing circuit 130. The second signalprocessing circuit 130 outputs, to the memory control circuit 115without any processing, the image data which is input from the reductioncircuit 111 and has a display size of 640×480. The memory controlcircuit 115 sequentially writes, at a pointer Pa in a DRAM 104 shown inFIG. 5A, the image data of the display size input from the second signalprocessing circuit 130, thereby transferring the entirely reduced imagedata to an entirely reduced image data memory area. The memory controlcircuit 115 reads out the entirely reduced image data in the DRAM 104 inaccordance with the display position, and outputs the entirely reducedimage data to a reconstruction circuit 120.

[0093] The reconstruction circuit 120 executes signal processing such aschroma encoding, band correction, or compositeness for the entirelyreduced image data input from the memory control circuit 115, therebyconverting the data into a TV (TeleVision) analog signal. Thereconstruction circuit 120 outputs the video signal to the monitor 121(see FIG. 7C).

[0094] When the AF mode is switched to the MF mode (the setting of theMF mode corresponds to a state in which the MF mode is set by the switchS_(MF) out of the switches 122), the CPU 100 stops auto focus controlbased on the AF data, switches the mode to the manual focus mode, andenables switches S_(F1) and S_(F2).

[0095] The switch S_(F1) is used to designate to drive the focus drivingunit 107 and drive the image sensing lens 106 to infinity. The switchS_(F2) is used to designate to drive the focus driving unit 107 anddrive the image sensing lens 106 to the closest focusing side.

[0096] An object image (see FIG. 2A) formed on the image sensing surfaceof the image sensing element 108 is photoelectrically converted by theimage sensing element 108, and sequentially read as CCD signals. EachCCD signal is converted from an analog signal into a digital signal bythe A/D converter 109. The digital image signal is input to the signalprocessing circuit 110. The signal processing circuit 110 includes thewhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies, to the CPU 100, AE data at theentire view angle, and AE data and AF data of partial image dataextracted by the extraction circuit 117.

[0097] The CPU 100 calculates stop control information and anaccumulation time on the basis of the AE data of the partial image data,and supplies the accumulation time (electronic shutter) information tothe driving unit of the image sensing element 108 and the stop controlinformation to the driving circuit 124 of the stop 123. The CPU 100 alsocalculates a brightness correction value on the basis of an exposurecorrection amount by the AE data of the partial image data and the AEdata at the entire view angle, and supplies the brightness correctionvalue to the second signal processing circuit 130.

[0098] As a result, the exposure amount of the partial image dataextracted by the extraction circuit 117 is controlled to obtainappropriate brightness.

[0099] The second signal processing circuit 130 performs, e.g., gainprocessing of multiplying, by the brightness correction value input fromthe CPU 100, the entirely reduced image data which is input from thereduction circuit 111 and has a display size of 640×480. The secondsignal processing circuit 130 outputs the resultant data to the memorycontrol circuit 115.

[0100] Hence, the entirely reduced image data output from the reductioncircuit 111 undergoes brightness correction to attain appropriatebrightness.

[0101] The extraction circuit 117 generates an address, and outputsimage data at a portion within the range of numerical values representedby pointers P1 and P2 shown in FIG. 2A from image signals of 1,600horizontal pixels and 1,200 vertical pixels of one frame that are inputfrom the signal processing circuit 110. When data falls outside therange of the numerical values represented by the pointer P1 (640horizontal pixels and 480 vertical pixels) and the pointer P2 (960horizontal pixels and 720 vertical pixels) shown in FIG. 2A, theextraction circuit 117 does not output any image data. The extractioncircuit 117 extracts a partial image of 320 horizontal pixels and 240vertical pixels without sampling (without decreasing the number ofpixels), and outputs an image signal representing the extracted partialimage to the third signal processing circuit 131.

[0102] The third signal processing circuit 131 outputs image data of the320×240 partial image input from the extraction circuit 117 to thememory control circuit 115 without any processing. The memory controlcircuit 115 sequentially writes the image data of the 320×240 partialimage input from the third signal processing circuit 131 at a pointer Pbin the DRAM 104 shown in FIG. 5A, thereby transferring the extractedpartial image data to an extracted partial image memory area.

[0103] The memory control circuit 115 reads out the 640×480 entirelyreduced image data and the 320×240 extracted partial image data in theDRAM 104 in accordance with the display position. The memory controlcircuit 115 synthesizes the entirely reduced image data and extractedpartial image, and outputs the resultant data as synthesized image datato the reconstruction circuit 120.

[0104] When the focus mode is switched from the AF mode to the MF modeby operating the switch S_(MF) in photographing, the monitor 121 changesfrom a state in which a sensed image is displayed as shown in FIG. 7C,and displays at appropriate brightness the entirely reduced image dataand the partial image extracted using a predetermined position of theimage as a center, as shown in FIG. 2C. While monitoring the focusadjustment image in FIG. 2C, the user can operate the switches S_(F1)and S_(F2), move the image sensing lens 106 forward or backward, andfocus it on an object to be sensed.

[0105] The focus adjustment image is an appropriate-brightness imagewhich is extracted using a predetermined position of an image sensingsignal as a center without decreasing the number of pixels. The usercan, therefore, confirm the same state as the focus state of a recordedimage.

[0106] The view angle adjustment image in FIG. 2C is simultaneouslydisplayed as an appropriate-brightness image on the monitor 121. Even ifthe user changes an object to be sensed, he/she can focus the imagesensing lens 106 on the object while confirming the entire view angle.

[0107] When the MF mode is switched to the AF mode (the switch S_(MF)out of the switches 122 is released), the CPU 100 inhibits theextraction circuit 117 and control of the memory control circuit 115from the extraction circuit 117. The extraction circuit 117 reads outentirely reduced image data in the DRAM 104, and outputs it to thereconstruction circuit 120, setting the states in FIGS. 7A to 7C. Afterthat, the CPU 100 is set in the AF mode.

[0108] In the third embodiment, entirely reduced image data correspondsto 640×480 pixels, and an extracted image corresponds to 320×240 pixels.Alternatively, as shown in FIGS. 8A to 8C, entirely reduced image datamay correspond to 320×240 pixels, and an extracted image may correspondto 640×480 pixels.

[0109] Also, images in FIGS. 8A to 8C and 2A to 2C may be switched.

[0110] The remaining arrangement, operation, and effects of the thirdembodiment are the same as those of the first embodiment, and adescription thereof will be omitted.

[0111] (Fourth Embodiment)

[0112] The fourth embodiment of the present invention will be describedwith reference to FIG. 6.

[0113] The basic system configuration of an image sensing apparatusaccording to the fourth embodiment is the same as that in FIG. 6according to the third embodiment described above. Display in the MFmode is illustrated in FIGS. 2A to 2C, similar to the first embodimentdescribed above. An example of system operation is shown in FIGS. 5A and5B, similar to the first embodiment. The fourth embodiment will beexplained with reference to these drawings.

[0114] The fourth embodiment is applied to an electronic camera havingan autofocus (to be referred to as AF hereinafter) function ofautomatically adjusting the focus on an image, and a manual focus (to bereferred to as MF hereinafter) function of adjusting the focus manually(including electrically).

[0115] Display operation of the image sensing apparatus according to thefourth embodiment will be explained.

[0116] More specifically, image data of 1,600 horizontal pixels and1,200 vertical pixels at the aspect ratio of the image size=4:3 isreduced to 640×480 by a reduction circuit (zooming circuit) 111. In theMF mode, a 320×240 partial image is extracted by an extraction circuit117. The 640×480 image data reduced by the reduction circuit 111 and the320×240 partial image extracted by the extraction circuit 117 aredisplayed on a monitor 121. This example will be explained.

[0117] An image sensing lens 106 can be moved by a focus driving unit107 along the optical axis. A stop 123 inserted in the optical axis isdriven by a stop driving unit 124. An image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing element 108 outputs image data of 1,600 horizontal pixels and1,200 vertical pixels. The monitor 121 displays image data of 640horizontal pixels and 480 vertical pixels.

[0118] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby an A/D converter 109. The digital image signal is input to a signalprocessing circuit 110. The signal processing circuit 110 includes awhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies, to a CPU 100, AE data at theentire view angle, and AE data and AF data of partial image dataextracted by the extraction circuit 117.

[0119] The CPU 100 executes following processing in the case that theimage sensing apparatus is set to a moving image mode where image dataare continuously recorded on the basis of a signal which permits animage sensing operation. More specifically, the CPU 100 calculates stopcontrol information and an accumulation time on the basis of the AE dataat the entire view angle, and supplies the accumulation time (electronicshutter) information to the driving unit of the image sensing element108 and the stop control information to the driving circuit 124 of thestop 123. The CPU 100 calculates a brightness correction value on thebasis of an exposure correction amount by the AE data at the entire viewangle and the AE data of the partial image data, and supplies thebrightness correction value to a third signal processing circuit 131.

[0120] As a result, the image data at the entire view angle which iscontrolled in exposure amount and output from the signal processingcircuit 110 attains appropriate brightness.

[0121] The reduction circuit 111 performs sampling or the like for pixeldata in accordance with 640 horizontal pixels and 480 vertical pixels asthe display size of the monitor 121, and outputs, to a second signalprocessing circuit 130, image data which is entirely reduced to ⅖(640×480) in horizontal and vertical directions. The second signalprocessing circuit 130 outputs, to a memory control circuit 115 withoutany processing, the image data which is input from the reduction circuit111 and has a display size of 640×480. The memory control circuit 115sequentially writes, at a pointer Pa in a DRAM 104 shown in FIG. 5A, theimage data which is input from the second signal processing circuit 130and has a display size of 640×480, thereby transferring the entirelyreduced image data to an entirely reduced image data memory area.

[0122] The extraction circuit 117 generates an address, and outputsimage data at a portion within the range of numerical values representedby pointers P1 and P2 shown in FIG. 2A from image signals of 1,600horizontal pixels and 1,200 vertical pixels of one frame that are inputfrom the signal processing circuit 110. When data falls outside therange of the numerical values represented by the pointer P1 (640horizontal pixels and 480 vertical pixels) and the pointer P2 (960horizontal pixels and 720 vertical pixels), the extraction circuit 117does not output any image data. The extraction circuit 117 extracts apartial image of 320 horizontal pixels and 240 vertical pixels withoutdecreasing the number of pixels, and outputs an image signalrepresenting the extracted partial image to the third signal processingcircuit 131.

[0123] The third signal processing circuit 131 performs, e.g., gainprocessing using the brightness correction value supplied from the CPU100 for image data of the 320×240 partial image input from theextraction circuit 117, and outputs the resultant data to the memorycontrol circuit 115.

[0124] Image data which is obtained by correcting the brightness of thepartial image and output from the third signal processing circuit 131attains appropriate brightness.

[0125] The memory control circuit 115 sequentially writes the image dataof the 320×240 partial image input from the third signal processingcircuit 131 at a pointer Pb in the DRAM 104 shown in FIG. 5A, therebytransferring the extracted partial image data to an extracted partialimage memory area.

[0126] The memory control circuit 115 reads out the 640×480 entirelyreduced image data and the 320×240 extracted partial image data in theDRAM 104 in accordance with the display position. The memory controlcircuit 115 synthesizes the entirely reduced image data and extractedpartial image, and outputs the resultant data as synthesized image datato a reconstruction circuit 120.

[0127] The switch S_(REC) is used to designate recording of a sensedimage. When the switch S_(REC) is turned on, the CPU 100 newly ensures aJPEG data memory area at a pointer Pc in DRAM 104 shown in FIG. 5A. Datasensed by the image sensing element 108 is converted into a digitalsignal by the A/D converter 109. The digital image signal is output as1,600×1,200 image data to the signal processing circuit 110, reductioncircuit 111, and extraction circuit 117. The reduction circuit 111reduces pixel data to ⅖ the pixel data amount in horizontal and verticaldirections by sampling. The reduction circuit 111 outputs the 640×480entirely reduced image data to the second signal processing circuit 130.

[0128] The second signal processing circuit 130 outputs the 640×480entirely reduced image data from the reduction circuit 111 to the memorycontrol circuit 115 and a raster/block conversion circuit 112 withoutany processing. The raster/block conversion circuit 112 converts rasterdata from a raster block conversion buffer memory 113 into block scandata, and outputs the block scan data to a compression circuit 114. Thecompression circuit 114 compresses data of each block into JPEG data,and outputs the JPEG data to the memory control circuit 115. The memorycontrol circuit 115 sequentially writes, at the pointer Pc in the DRAM104 shown in FIG. 5A, the JPEG data input from the compression circuit114, thereby transferring the JPEG data to the JPEG data memory area.The CPU 100 reads out the JPEG data from the pointer PC in the DRAM 104shown in FIG. 5A, and writes the data as a JPEG file in a storage medium102.

[0129] Similarly, the extraction circuit 117 extracts a 320×240 partialimage from the 1,600×1,200 image data input from the signal processingcircuit 110, and outputs the extracted partial image to the third signalprocessing circuit 131.

[0130] The third signal processing circuit 131 performs brightnesscorrection for brightness information of image data of the 320×240partial image input from the extraction circuit 117, gives appropriatebrightness to the image data of the 320×240 partial image, and outputsthe image data to the memory control circuit 115. The memory controlcircuit 115 transfers the image data of the partial image to the pointerPb in the DRAM 104 shown in FIG. 5A. The memory control circuit 115reads out the 640×480 entirely reduced image data in the DRAM 104 andthe 320×240 partial image extracted by the extraction circuit 117 inaccordance with the display position. The memory control circuit 115synthesizes the entirely reduced image data and the partial imageextracted by the extraction circuit 117, and outputs the resultant dataas synthesized image data to the reconstruction circuit 120.

[0131] The CPU100 executes following processing in the case that theimage sensing apparatus is set to a moving image mode where image dataare continuously recorded on the basis of a signal which permits animage sensing operation. More specifically, the CPU controls the imagesensing apparatus such that the exposure amount is controlled and imagedata of all image angle outputted from the signal processing circuit 110become to have appropriate brightness as the present embodiment, in thecase that the moving image mode has been selected.

[0132] Further, the CPU100 executes following processing in the casethat the image sensing apparatus is set to a still image mode wherestill image data is recorded on the basis of a signal which permits animage sensing operation. More specifically, the CPU controls the imagesensing apparatus such that the exposure amount of the partial imagedata extracted by the extraction circuit 117 is controlled and thepartial image data become to have appropriate brightness as the thirdembodiment.

[0133] The remaining arrangement, operation, and effects of the fourthembodiment are the same as those of the first embodiment, and adescription thereof will be omitted.

[0134] (Fifth Embodiment)

[0135] The fifth embodiment of the present invention will be describedwith reference to FIG. 6.

[0136] The basic system configuration of an image sensing apparatusaccording to the fifth embodiment is the same as that in FIG. 6according to the third embodiment described above. Display in the MFmode is illustrated in FIGS. 2A to 2C, similar to the first embodimentdescribed above. An example of system operation is shown in FIGS. 5A and5B, similar to the third embodiment. The fifth embodiment will beexplained with reference to these drawings.

[0137] The fifth embodiment is applied to an electronic camera having anautofocus (to be referred to as AF hereinafter) function ofautomatically adjusting the focus on an image, and a manual focus (to bereferred to as MF hereinafter) function of adjusting the focus manually(including electrically).

[0138] Display operation of the image sensing apparatus according to thefifth embodiment will be explained.

[0139] More specifically, image data of 1,600 horizontal pixels and1,200 vertical pixels at the aspect ratio of the image size=4:3 isreduced to 640×480 by a reduction circuit (zooming circuit) 111. In theMF mode, a 320×240 partial image is extracted by an extraction circuit117. The 640×480 image data reduced by the reduction circuit 111 and the320×240 partial image extracted by the extraction circuit 117 aredisplayed on a monitor 121. This example will be explained.

[0140] An image sensing lens 106 can be moved by a focus driving unit107 along the optical axis. A stop 123 inserted in the optical axis isdriven by a stop driving unit 124. An image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing element 108 outputs image data of 1,600 horizontal pixels and1,200 vertical pixels. The monitor 121 displays image data of 640horizontal pixels and 480 vertical pixels.

[0141] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby an A/D converter 109. The digital image signal is input to a signalprocessing circuit 110. The signal processing circuit 110 includes awhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies, to a CPU 100, AE data at theentire view angle, and AE data and AF data of partial image dataextracted by the extraction circuit 117.

[0142] The CPU 100 calculates stop control information and an exposurecorrection amount serving as an accumulation time (electronic shutter)on the basis of the AE data at the entire view angle. The CPU 100calculates a brightness correction value on the basis of the exposurecorrection amount by the AE data at the entire view angle and the AEdata of the partial image data.

[0143] The CPU 100 determines whether the brightness correction valuecan be corrected, and if so, supplies the accumulation time (electronicshutter) information to the driving unit of the image sensing element108 and the stop control information to the driving circuit 124 of thestop 123. Also, the CPU 100 supplies the brightness correction value toa second signal processing circuit 130.

[0144] In this manner, the exposure amount of the partial image dataextracted by the extraction circuit 117 is controlled, obtainingappropriate brightness.

[0145] If the brightness correction value cannot be corrected, the CPU100 corrects the exposure correction amount so as to change thebrightness correction value to a correctable value, and supplies theexposure correction amount to the accumulation time (electronic shutter)of the image sensing element 108 and the stop driving unit 124.

[0146] The CPU 100 executes brightness correction calculation on thebasis of the exposure correction amount and the AE data at the entireview angle, and supplies the brightness correction value to the secondsignal processing circuit 130.

[0147] The CPU 100 calculates a brightness correction value on the basisof the exposure correction amount and the AE data of the partial imagedata, and supplies the brightness correction value to a third signalprocessing circuit 131.

[0148] Accordingly, the exposure amount of the partial image dataextracted by the extraction circuit 117 is controlled, and noappropriate brightness is obtained.

[0149] The reduction circuit 111 performs sampling or the like for pixeldata in accordance with 640 horizontal pixels and 480 vertical pixels asthe display size of the monitor 121, and outputs, to the second signalprocessing circuit 130, image data which is entirely reduced to ⅖(640×480) in horizontal and vertical directions.

[0150] The second signal processing circuit 130 performs, e.g., gainprocessing of multiplying, by the brightness correction value input fromthe CPU 100, the entirely reduced image data which is input from thereduction circuit 111 and has a display size of 640×480. The secondsignal processing circuit 130 outputs the resultant data to a memorycontrol circuit 115.

[0151] The brightness of the entirely reduced image data output from thereduction circuit 111 is therefore corrected to attain appropriatebrightness.

[0152] The memory control circuit 115 sequentially writes, at a pointerPa in a DRAM 104 shown in FIG. 5A, the image data which is input fromthe second signal processing circuit 130 and has a display size of640×480, thereby transferring the entirely reduced image data to anentirely reduced image data memory area.

[0153] The extraction circuit 117 generates an address, and outputsimage data at a portion within the range of numerical values representedby pointers P1 and P2 shown in FIG. 2A from image signals of 1,600horizontal pixels and 1,200 vertical pixels of one frame that are inputfrom the signal processing circuit 110. When data falls outside therange of the numerical values represented by the pointer P1 (640horizontal pixels and 480 vertical pixels) and the pointer P2 (960horizontal pixels and 720 vertical pixels), the extraction circuit 117does not output any image data. The extraction circuit 117 extracts apartial image of 320 horizontal pixels and 240 vertical pixels withoutdecreasing the number of pixels, and outputs an image signalrepresenting the extracted partial image to the third signal processingcircuit 131.

[0154] The third signal processing circuit 131 performs, e.g., gainprocessing using the brightness correction value supplied from the CPU100 for image data of the 320×240 partial image input from theextraction circuit 117, and outputs the resultant data to the memorycontrol circuit 115.

[0155] Image data which is obtained by correcting the brightness of thepartial image and output from the third signal processing circuit 131attains appropriate brightness.

[0156] The memory control circuit 115 sequentially writes the image dataof the 320×240 partial image input from the third signal processingcircuit 131 at a pointer Pb in the DRAM 104 shown in FIG. 5A, therebytransferring the extracted partial image data to an extracted partialimage memory area.

[0157] The memory control circuit 115 reads out the 640×480 entirelyreduced image data and the 320×240 extracted partial image data in theDRAM 104 in accordance with the display position. The memory controlcircuit 115 synthesizes the entirely reduced image data and extractedpartial image, and outputs the resultant data as synthesized image datato a reconstruction circuit 120.

[0158] The remaining arrangement, operation, and effects of the fifthembodiment are the same as those of the first embodiment, and adescription thereof will be omitted.

[0159] (Sixth Embodiment)

[0160] The sixth embodiment of the present invention will be describedwith reference to FIG. 6.

[0161] The basic system configuration of an image sensing apparatusaccording to the sixth embodiment is the same as that in FIG. 6according to the third embodiment described above. Display in the MFmode is illustrated in FIGS. 2A to 2C, similar to the first embodimentdescribed above. An example of system operation is shown in FIGS. 5A and5B, similar to the third embodiment. The sixth embodiment will beexplained with reference to these drawings.

[0162] The sixth embodiment is applied to an electronic camera having anautofocus (to be referred to as AF hereinafter) function ofautomatically adjusting the focus on an image, and a manual focus (to bereferred to as MF hereinafter) function of adjusting the focus manually(including electrically).

[0163] Display operation of the image sensing apparatus according to thesixth embodiment will be explained.

[0164] More specifically, image data of 1,600 horizontal pixels and1,200 vertical pixels at the aspect ratio of the image size=4:3 isreduced to 640×480 by a reduction circuit (zooming circuit) 111. In theMF mode, a 320×240 partial image is extracted by an extraction circuit117. The 640×480 image data reduced by the reduction circuit 111 and the320×240 partial image extracted by the extraction circuit 117 aredisplayed on a monitor 121. This example will be explained.

[0165] An image sensing lens 106 can be moved by a focus driving unit107 along the optical axis. A stop 123 inserted in the optical axis isdriven by a stop driving unit 124. An image sensing element 108 isinserted in the optical axis of the image sensing lens 106. An objectimage having passed through the image sensing lens 106 is formed on theimage sensing surface of the image sensing element 108. The imagesensing element 108 outputs image data of 1,600 horizontal pixels and1,200 vertical pixels. The monitor 121 displays image data of 640horizontal pixels and 480 vertical pixels.

[0166] The object image (see FIG. 2A) formed on the image sensingsurface of the image sensing element 108 is photoelectrically convertedby the image sensing element 108, and sequentially read as CCD signals.Each CCD signal is converted from an analog signal into a digital signalby an A/D converter 109. The digital image signal is input to a signalprocessing circuit 110. The signal processing circuit 110 includes awhite balance adjustment circuit, gamma correction circuit, and YCprocessing circuit. The signal processing circuit 110 outputs image dataof 1,600 horizontal pixels and 1,200 vertical pixels processed by thesecircuits to the reduction circuit 111 and extraction circuit 117. Thesignal processing circuit 110 supplies, to a CPU 100, AE data at theentire view angle, and AE data and AF data of partial image dataextracted by the extraction circuit 117.

[0167] The CPU 100 calculates stop control information and anaccumulation time on the basis of the AE data of the partial image data,and supplies the accumulation time (electronic shutter) information tothe driving unit of the image sensing element 108 and the stop controlinformation to the driving circuit 124 of the stop 123. The CPU 100calculates a brightness correction value on the basis of an exposurecorrection amount by the AE data of the partial image data and the AEdata at the entire view angle such that the image at the entire viewangle becomes lower in brightness value than the partial image. The CPU100 supplies the brightness correction value to a second signalprocessing circuit 130.

[0168] As a result, the exposure amount of the partial image dataextracted by the extraction circuit 117 is controlled to obtainappropriate brightness.

[0169] The second signal processing circuit 130 performs, e.g., gainprocessing of multiplying, by the brightness correction value input fromthe CPU 100, the entirely reduced image data which is input from thereduction circuit 111 and has a display size of 640×480. The secondsignal processing circuit 130 outputs the resultant data to a memorycontrol circuit 115.

[0170] The brightness of the entirely reduced image data output from thereduction circuit 111 is therefore corrected to attain appropriatebrightness.

[0171] The extraction circuit 117 generates an address, and outputsimage data at a portion within the range of numerical values representedby pointers P1 and P2 shown in FIG. 2A from image signals of 1,600horizontal pixels and 1,200 vertical pixels of one frame that are inputfrom the signal processing circuit 110. When data falls outside therange of the numerical values represented by the pointer P1 (640horizontal pixels and 480 vertical pixels) and the pointer P2 (960horizontal pixels and 720 vertical pixels), the extraction circuit 117does not output any image data. The extraction circuit 117 extracts apartial image of 320 horizontal pixels and 240 vertical pixels withoutdecreasing the number of pixels, and outputs an image signalrepresenting the extracted partial image to a third signal processingcircuit 131.

[0172] The third signal processing circuit 131 outputs the image data ofthe 320×240 partial image from the extraction circuit 117 to the memorycontrol circuit 115 without any processing.

[0173] The memory control circuit 115 sequentially writes the image dataof the 320×240 partial image input from the third signal processingcircuit 131 at a pointer Pb in a DRAM 104 shown in FIG. 5A, therebytransferring the extracted partial image data to an extracted partialimage memory area.

[0174] The memory control circuit 115 reads out the 640×480 entirelyreduced image data and the 320×240 extracted partial image data in theDRAM 104 in accordance with the display position. The memory controlcircuit 115 synthesizes the entirely reduced image data and extractedpartial image, and outputs the resultant data as synthesized image datato a reconstruction circuit 120.

[0175] The remaining arrangement, operation, and effects of the sixthembodiment are the same as those of the first embodiment, and adescription thereof will be omitted.

[0176] The above-described embodiments can be changed or modified withinthe spirit and scope of the present invention.

[0177] For example, a distance measurement device capable of separatelymeasuring object distances corresponding to a plurality of regionsincluding the central region within the viewfinder may be furtherarranged. This device may have a multipoint distance measurementautofocus function of automatically operating the focus adjustmentmember to adjust the focus.

[0178] The image sensing apparatus may have a macro function.

[0179] The image sensing lens system may have a function of adjustingthe stop in order to confirm the focus state of an actually sensedimage.

[0180] In the above-described embodiments, the electronic shutterfunction of the image sensing element is used. A mechanical shutter maybe adopted.

[0181] In the use of the autofocus function, a sampled image andextracted image may be synthesized and displayed after focus adjustment.

[0182] A detection device which detects whether an image is in focus maybe further arranged. When the detection device detects that the image isin focus, the device may output to the image display unit an instructionsignal for synchronizing and displaying a sampled image and extractedimage.

[0183] In this case, when the detection device detects that the image isout of focus, the device may output to the image display unit aninstruction signal for canceling synthetic display of a sampled imageand extracted image. At the same time, exposure may be so controlled asto set the sampled image to appropriate brightness.

[0184] In multipoint distance measurement, it is also possible tosynthesize and display an extracted image and sampled image whichcorrespond to an in-focus region out of a plurality of distancemeasurement regions after focus adjustment.

[0185] A detection device which detects whether the focus adjustmentmember has been operated may be further arranged. When the detectiondevice detects that the focus adjustment member has been operated, thedevice may output to the image display unit an instruction signal forsynchronizing and displaying a sampled image and extracted image.

[0186] In this case, when the detection device detects that the focusadjustment member has not been operated, the device may output to theimage display unit an instruction signal for canceling synthetic displayof a sampled image and extracted image. At the same time, exposure maybe so controlled as to set the sampled image to appropriate brightness.

[0187] When the detection device detects that the focus adjustmentmember has not been operated, the device may output, to the imagedisplay unit after the lapse of a predetermined time, an instructionsignal for canceling synthetic display of a sampled image and extractedimage. At the same time, exposure may be so controlled as to set thesampled image to appropriate brightness.

[0188] A macro switch which switches the image sensing apparatus tomacro photographing may be further arranged to synthesize and display asampled image and extracted image at the end of macro photographing.

[0189] In this case, when macro photographing is canceled, the macroswitch may output to the image display unit an instruction signal forcanceling synthetic display of a sampled image and extracted image. Atthe same time, exposure may be so controlled as to set the sampled imageto appropriate brightness.

[0190] A stop-down switching device which switches the image sensingapparatus to a stop-down mode may be further arranged. When the imagesensing apparatus is switched to the stop-down mode, the stop-downswitching device may output to the image display unit an instructionsignal for canceling synthetic display of a sampled image and extractedimage.

[0191] When the stop-down mode is canceled, the stop-down switchingdevice may output to the image display unit an instruction signal forcanceling synthetic display of a sampled image and extracted image. Atthe same time, exposure may be so controlled as to set the sampled imageto appropriate brightness.

[0192] [Other Embodiment]

[0193] The objects of the above-described embodiments are also achievedwhen a storage medium (or recording medium) which stores softwareprogram codes for realizing the functions of the above-describedembodiments is supplied to a system or apparatus, and the computer (orthe CPU or MPU) of the system or apparatus reads out and executes theprogram codes stored in the storage medium. In this case, the programcodes read out from the storage medium realize the functions of theabove-described embodiments, and the storage medium which stores theprogram codes constitutes the present invention. The functions of theabove-described embodiments are realized when the computer executes thereadout program codes. Also, the functions of the above-describedembodiments are realized when an OS (Operating System) or the likerunning on the computer performs part or all of actual processing on thebasis of the instructions of the program codes.

[0194] The functions of the above-described embodiments are alsorealized when the program codes read out from the storage medium arewritten in the memory of a function expansion card inserted into thecomputer or the memory of a function expansion unit connected to thecomputer, and the CPU of the function expansion card or functionexpansion unit performs part or all of actual processing on the basis ofthe instructions of the program codes.

[0195] When the present invention is applied to the storage medium, thestorage medium stores program codes corresponding to the above-describedprocedures.

[0196] As has been described above in detail, according to the imagesensing method and apparatus of the embodiments, the focus state of animage sensed by a solid-state image sensing element having a largenumber of pixels can be confirmed on an image display device having asmall number of pixels even for an object with a large brightnessdifference. The user can manually adjust the focus at a high precisionwhile confirming an entire frame and focus adjustment frame free fromany timing difference. The circuit scale does not increase, and even ina synthetic display state, an increase in power consumption and thememory arrangement can be minimized.

[0197] In the third embodiment, the focusing area achieves opticallyproper exposure, and the view angle confirmation image obtainsappropriate brightness. This is effective for focusing in still picturephotographing.

[0198] In the fourth embodiment, the recording image (for confirming aview angle) achieves optically proper exposure, and the focusing areaattains appropriate brightness. This is effective for focusing in movingpicture photographing.

[0199] The fifth embodiment is effective for focusing in still picturephotographing when the image exceeds the brightness correction(electrical) range.

[0200] In the sixth embodiment, the focusing effect can be furtherenhanced by setting the view angle confirmation image to appropriatebrightness or lower.

[0201] The storage medium of the embodiments makes it possible tosmoothly control the above-described image sensing apparatus.

[0202] As has been described above, the present invention allowsquickly, reliably confirming an in-focus state with a simplearrangement.

[0203] The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to apprise the public of thescope of the present invention the following claims are made.

What is claimed is:
 1. An image sensing apparatus comprising: an imagesensing unit adapted to photoelectrically convert an object image; afirst image generation unit adapted to generate a first image obtainedfrom said image sensing unit; a second image generation unit adapted togenerate a second image corresponding to a predetermined region of theobject image obtained from said image sensing unit; an exposure controlunit adapted to control an exposure amount so that the second imagebecome to have appropriate brightness; and a brightness correction unitadapted to correct signal of the first image so that the first imagebecome to have appropriate brightness.
 2. The apparatus according toclaim 1, further comprising a display control unit adapted to control todisplay the first image and the second image.
 3. The apparatus accordingto claim 2, wherein said display control unit displays combined image ofthe first image and the second image.
 4. The apparatus according toclaim 2, further comprising an image display device adapted to displaythe image on the basis of the control of said display control unit,wherein said image display device displays the image with a number ofpixels smaller than a number of pixels of said image sensing unit. 5.The apparatus according to claim 1, further comprising: a manual focusfunction adapted to adjust a focus by manually operating a focusadjustment member; and an auto-focus function adapted to adjust thefocus by automatically operating the focus adjustment member, whereinsaid display control unit controls to display the first image and thesecond image after the focus adjustment operation completed.
 6. Theapparatus according to claim 5, further comprising a switching deviceadapted to switch a first mode where the focus is automatically adjustedand a second mode where the focus is manually adjusted, wherein saiddisplay control unit controls to display the first image and the secondimage in the case that a mode is set to the second mode by saidswitching device.
 7. An image sensing apparatus comprising: an imagesensing unit adapted to photoelectrically convert an object image; afirst image generation unit adapted to generate a first image obtainedfrom said image sensing unit; a second image generation unit adapted togenerate a second image corresponding to a predetermined region of theobject image obtained from said image sensing unit; an exposure controlunit adapted to control an exposure amount so that the first imagebecome to have appropriate brightness; and a brightness correction unitadapted to correct signal of the second image so that the second imagebecome to have appropriate brightness.
 8. The apparatus according toclaim 7, further comprising a display control unit adapted to control todisplay the first image and the second image.
 9. The apparatus accordingto claim 8, wherein said display control unit displays combined image ofthe first image and the second image.
 10. The apparatus according toclaim 8, further comprising an image display device adapted to displaythe image on the basis of the control of said display control unit,wherein said image display device displays the image with a number ofpixels smaller than a number of pixels of said image sensing unit. 11.The apparatus according to claim 7, further comprising: a manual focusfunction adapted to adjust a focus by manually operating a focusadjustment member; and an auto-focus function adapted to adjust thefocus by automatically operating the focus adjustment member, whereinsaid display control unit controls to display the first image and thesecond image after the focus adjustment operation completed.
 12. Theapparatus according to claim 11, further comprising a switching deviceadapted to switch a first mode where the focus is automatically adjustedand a second mode where the focus is manually adjusted, wherein saiddisplay control unit controls to display the first image and the secondimage in the case that a mode is set to the second mode by saidswitching device.
 13. An image sensing apparatus having a first mode anda second mode, comprising: an image sensing unit adapted tophotoelectrically convert an object image; a first image generation unitadapted to generate a first image obtained from said image sensing unit;a second image generation unit adapted to generate a second imagecorresponding to a predetermined region of the object image obtainedfrom said image sensing unit; an exposure control unit adapted tocontrol an exposure so that the image become to have appropriatebrightness; a brightness correction unit adapted to correct signal ofthe image so that the image become to have appropriate brightness; and acontrol unit adapted to control the exposure so that the first imagebecome to have appropriate brightness and control to correct the signalof the first image so that the second image become to have appropriatebrightness in the case that the first mode is selected, and control theexposure so that the second image become to have appropriate brightnessand control to correct the signal of the first image so that the firstimage become to have appropriate brightness in the case that the secondmode is selected.
 14. The apparatus according to claim 13, wherein saidfirst mode is a mode where a still image is sensed and said second modeis a mode where moving images are continuously sensed on the basis of asignal which permits image sensing.
 15. The apparatus according to claim13, further comprising a display control unit adapted to control todisplay the first image and the second image.
 16. The apparatusaccording to claim 15, wherein said display control unit displayscombined image of the first image and the second image.
 17. Theapparatus according to claim 15, further comprising an image displaydevice adapted to display the image on the basis of the control of saiddisplay control unit, wherein said image display device displays theimage with a number of pixels smaller than a number of pixels of saidimage sensing unit.
 18. The apparatus according to claim 13, furthercomprising: a manual focus function adapted to adjust a focus bymanually operating a focus adjustment member; and an auto-focus functionadapted to adjust the focus by automatically operating the focusadjustment member, wherein said display control unit controls to displaythe first image and the second image after the focus adjustmentoperation completed.
 19. The apparatus according to claim 18, furthercomprising a switching device adapted to switch a first mode where thefocus is automatically adjusted and a second mode where the focus ismanually adjusted, wherein said display control unit controls to displaythe first image and the second image in the case that a mode is set tothe second mode by said switching device.
 20. An image sensing methodcomprising the steps of: photo-electrically converting an object imageby an image sensing unit; generating a first image obtained from saidimage sensing unit by a first image generation unit; generating a secondimage corresponding to a predetermined region of the object imageobtained from said image sensing unit by a second image generation unit;controlling an exposure amount so that the second image become to haveappropriate brightness by an exposure control unit; and correctingsignal of the first image so that the first image become to haveappropriate brightness by a brightness correction unit.
 21. An imagesensing method comprising the steps of: photo-electrically converting anobject image by an image sensing unit; generating a first image obtainedfrom said image sensing unit by a first image generation unit;generating a second image corresponding to a predetermined region of theobject image obtained from said image sensing unit by a second imagegeneration unit; controlling an exposure amount so that the first imagebecome to have appropriate brightness by an exposure control unit; andcorrecting signal of the second image so that the second image become tohave appropriate brightness by a brightness correction unit.
 22. Animage sensing method having a first mode and a second mode, comprisingthe steps of: photo-electrically converting an object image by an imagesensing unit; generating a first image obtained from said image sensingunit by a first image generation unit; generating a second imagecorresponding to a predetermined region of the object image obtainedfrom said image sensing unit by a second image generation unit;controlling an exposure so that the image become to have appropriatebrightness by an exposure control unit; correcting signal of the imageso that the image become to have appropriate brightness by a brightnesscorrection unit; and controlling the exposure so that the first imagebecome to have appropriate brightness and controlling to correct thesignal of the first image so that the second image become to haveappropriate brightness in the case that the first mode is selected, andcontrolling the exposure so that the second image become to haveappropriate brightness and controlling to correct the signal of thefirst image so that the first image become to have appropriatebrightness in the case that the second mode is selected, by a controlunit.